This invention relates generally to the construction industry and, more particularly, to specialized corner beads, and the like, which provide one or more screed surfaces for the application of mortar for facing materials.
The traditional method of installing tile or stone onto an existing wall uses at least two xe2x80x9cfloat strips,xe2x80x9d typically wooden laths, imbedded into a bed of mortar troweled around a metal mesh having diamond-shaped openings. The mortar is xe2x80x9cfloatedxe2x80x9d between and around the float strips, and screeded off with a straight-edge against the float strips to form a xe2x80x9csetting bedxe2x80x9d for the subsequent installation of the facing material. The float strips are pulled out of the mortar, and the rectangular channels left behind are then filled with mortar and troweled flat, after which the float strips are washed off and saved for the next floating. When the setting bed or layer of mortar is complete, the tile or stone is applied with cement to the vertical mortar surface, and the wall is finished.
Various tools and techniques have been proposed over the years to make this process more efficient or more predictable. According to U.S. Pat. No. 4,128,982, the basic process outlined above remains the same, with the exception that a diamond mesh plastic lath is used in place of the metal lath. According to the inventors, because of the humid areas in which tile walls are often put, the metal lath begins to rust very quickly after installation and contributes to the rapid deterioration of the wall supporting structure. In addition, the diamond mesh has very sharp points, and is very difficult to cut with tin snips and install without somehow in the process winding up with multiple cuts and scratches.
The same or a similar process is used in conjunction with the application of mud-set floor tiles. According to U.S. Pat. No 5,154,536, most tile contractors use a wood float strip application which involves setting a 1xc2xd inch by xe2x85x9 wood strip on a previously applied row of mortar. The wood strip is pressed into place and leveled to a height of 1xc2xc inch above a plywood subfloor while the mortar row is still soft. Thereafter, mortar is poured to a height of 1xc2xc inches to form a cold joint with the previously-applied mortar row. Some of the problems involved with wood float strip application include the fact that such cold joints almost always crack with ease, and it is difficult to keep the edges of the wood level.
According to the ""536 patent, this problem is addressed by providing a screed guide or rail formed of hardened, folded metal. The guide comprises two parts, a top xe2x80x9cTxe2x80x9d shape, and a bottom inverted xe2x80x9cTxe2x80x9d shape. The top xe2x80x9cTxe2x80x9d fits into the lower inverted xe2x80x9cTxe2x80x9d, thereby forming an elongated wide-based I-beam. The screed guide or rail is attached to a subfloor panel where mortar or cement will be laid. The screed guide or rail can then be adjusted as to height by sliding the top piece up or down to create a level surface to screed from. Once the surface is made level, the two parts may be bolted together through elongated slots. Mortar or cement is then poured around the screed guide or rail, which becomes a metal reinforcement of the cement or mortar. The lips provided on the top and bottom flanges formed by the tops of the respective xe2x80x9cTxe2x80x9d s are significant in that they lock the cement or mortar bed to both sides of the screed guide or rail. Also, the top flange is significantly narrower than the bottom flange to enable the user to easily secure the screed guide or rail to the subflooring or to a wall.
U.S. Pat. No. 5,722,746 discloses a corner tile support strip for use in conjunction with a tile-covered structure. The strip is attached between the vertical surface and the vertical leg sections of the corner tiles, and includes an xe2x80x9cL-shapedxe2x80x9d first main body screed and an elongated rectangular stress barrier member, with the stress barrier member being attached to the screed by caulking.
U.S. Pat. No. 5,970,671 describes a construction accessory for use with a construction panel. The accessory includes a flange having an inner surface adapted to face the construction panel, and an outer surface opposite the inner surface. The flange further includes at least one perforation extending through the flange between the inner surface and the outer surface and a depression in the inner surface. The depression is in communication with said at least one perforation.
U.S. Pat. No. 5,079,880 is directed to a trim for trimming out or finishing contemporary, one-piece fiberglass and acrylic bathtubs and shower stalls. The trim includes framing pieces which are positioned around the edges of the surrounding wall portion of a bathtub or shower stall after the bathtub has been installed. A large flange portion of each framing piece is secured to the wood stud framing or wall using wood screws. The large flange portion and a small flange portion extend from a base portion and form a cavity for receiving an edge of a dry wall sheet. The trim may include separate finishing pieces which snap-on to an outer surface of the small flange portion of the framing pieces. Alternatively, the small flange portion of the framing pieces may be formed with a finished surface thereby dispensing with the need for separate finishing pieces.
U.S. Pat. No. 4,624,087 resides in a formed sheet metal corner bead for use with drywall. The bead includes a channel portion for mounting on the edge of one sheet of wallboard, and a narrow double layer flange extending laterally outward to cover the edge of a second sheet of wallboard which forms an exterior corner with the first sheet of wallboard.
Thus, although the prior art includes various articles providing screed surfaces and beads for use with drywall corners, the need remains for a corner or wall strip that helps to finish the transition from a tile or stone facing to a wall section that does not feature such a facing.
This invention is directed to articles for preparing a uniform thickness bed of mortar or xe2x80x98mudxe2x80x99 on a wall to receive a facing material. Broadly, an article according to the invention includes a length of formed stock, such as plastic, aluminum or steel in a multi-foot length, preferably 8 or 10-foot lengths. The article includes a first edge oriented lengthwise along the stock for contact against the surface of a first wall to be faced, and a second edge parallel and spaced apart from the first edge by a predetermined distance, the second edge providing a screed against which a tool may be drawn to smooth a cement layer on the first wall having a thickness substantially equal to the predetermined distance.
Different embodiments of the invention are applicable to different construction situations, including flat walls, outside corners, inside corners, above doorways and other openings. In one embodiment, a corner bead is used to create a finished edge with tile or stone on one side of a corner, with a drywall mud finish on the other side of the corner. The article is installed after installation of drywall board, and prior to installation of cement and drywall mud. During installation of tile or stone, an edge of the article is used as a screed, and ultimately becomes the finished edge of the tile or stone installed. Use of the article eliminates the labor typically required to fill the gap behind the tile or stone caused by the addition of the cement or Durock(copyright). A no-trim version of the corner bead embodiment eliminates the need for bull-nose tile tri or polished stone edges. Through appropriate adjustment, the article may accommodate different tile or stone thickness.
A straight wall bead embodiment is used to create a finished edge with tile or stone on one portion of a flat wall, and drywall mud finish on the other side of the flat wall. Any wall where stone or tile meets drywall on a flat surface is a candidate for this embodiment. A no-trim version eliminates the need for bull-nose tile trim or polished stone edges.
An inside corner embodiment is used on an inside corner where stone or tile meets with stone or tile. Using the inside corner unit as a screed, the excess cement is removed using a straight edge from one inside corner unit to the appropriate screed, leaving a flat edge on cement. The inside corner unit, acting as a screed, can be used with any other form of screed whether inside corner, outside corner, or straight wall. The inside corner embodiment also helps to eliminate corner cracks, as it provides both corner planes in a single unit, and is completely embedded in cement.
An outside corner embodiment is used on an outside corner where stone or tile meets with stone or tile. Appropriate uses would include shower seats, curbs, doorways, niches, and windows. The unit is installed in the same manner as the inside corner embodiment, and similarly, acts as a screed, leaving a flat edge on cement upon completion.
Different tile-holding embodiments, with and without a screed, are used above doors and windows, or any opening to be tiled. Articles according to this embodiment may be installed horizontally above an opening after drywall installation and prior to cement application. The stone or tile is set on the protruding lip of the tile hold u nit, and prevents slipping or sagging of the stone until the adhesive or thin-set dries, or until proper bonding is achieved. When tile trim is placed on the protruding lip of the unit, the protrusion is concealed within the grout joint.